Defences to Murder

This article explains the available defences (both complete and partial defences) to the charge of murder in New South Wales. Self-defence (to protect property or prevent criminal trespass), duress and necessity are not available to defend a charge of murder. 

How Offences Are Proven:

In order for a person to be found guilty of any offence, the Prosecution must prove every element of the offence to the standard of beyond a reasonable doubt. 

The ‘elements’ of an offence are the ingredients that make up the offence. All offences contain physical elements (such as driving a motor vehicle, hitting or slapping another person, or being in possession of a drug) and mental or ‘fault’ elements (such as intent, recklessness or knowledge). When the Prosecution is unable to prove each and every element of the offence to the standard of beyond a reasonable doubt, the person charged should be found not guilty.

Even if the Prosecution can satisfy all the elements of an offence to the standard of beyond reasonable doubt, the person charged may raise a defence to the charge which, if accepted, means they are not criminally liable and therefore not guilty of the offence. 

Complete Defences v Partial Defences:

A ‘complete’ defence fully absolves a Defendant of criminal liability meaning they are not guilty of the offence. A ‘partial’ defence, if accepted, operates to reduce the charge of murder to the charge of manslaughter. 

Complete Defences:

Reasonable Doubt:

As explained above, if the Prosecution cannot prove each element of an offence to the standard of beyond reasonable doubt, the Defendant should be found not guilty and acquitted of the offence. This applies to all offences including the charge of murder. 

The elements of a murder charge are:

1. The victim died, 
2. The act or omission of the accused caused the death of the victim,
3. The act of the accused was without lawful cause or excuse, 
4. The act or omission causing death was done by the accused with the intention to kill or do grievous bodily harm, foreseeing that it was probable that the death would result from the act or omission, or an accomplice to commit a serious indictable offence punishable by imprisonment for life or 25 years. 

If the Prosecution fails to prove any of the above elements beyond a reasonable doubt, the accused must be acquitted of the offence. 

Automatism:

The defence of automatism is based on the principle that a person is not responsible for an act that was committed involuntarily. Where an act that is otherwise criminal is done in a state of automatism then no crime has been committed, and the accused must be found not guilty. The term automatism is used to describe an assertion by the defence that their conduct was not voluntary. 

Insanity or Mental Impairment:

Where a person is suffering from a mental illness or cognitive impairment at the time of committing an offence, with that impairment being so significant that the person did not know their actions were wrong, or did not know the nature and quality of their actions, they may be able to rely on the defence of mental or cognitive impairment (previously known as the defence of insanity). 

The Mental Health and Cognitive Impairment Forensic Provisions Act 2020 at Section 28 provides that a person is not criminally responsible for an offence if, at the time of carrying out the offence, the person had a mental or cognitive impairment (or both) that had the effect that the person:

1. Did not know the nature and quality of the act, or 
2. Did not know that the act was wrong (that is, the person could not with a moderate degree of sense and composure about whether the act, as perceived by reasonable people, was wrong). 

It is important to note that raising a mental impairment in criminal proceedings results in a different process occurring, and whilst the person may not be held to be criminally responsible, there is an entirely separate Court process that exists which might nevertheless result in the incarceration of the person (but typically in a mental institution instead of a correctional centre). More information about this can be found at (link to) Special Hearings. 

Partial Defences:

Excessive Self-Defence:

Section 421 of the Crimes Act 1900 creates a separate provision in relation to self-defence that inflicts death. That Section says that if a person uses force that involves the infliction of death and the conduct is not a reasonable response in the circumstances as he or she perceives then but the person believed their conduct was necessary to defend themselves, another person or prevent the unlawful deprivation of their or another liberty that the person is not criminally responsible for murder but is to be found guilty of manslaughter. 

Extreme Provocation:

Section 23(2) of the Crimes Act 1900 creates the partial defence of extreme provocation which, if accepted, would result in the accused being guilty of manslaughter instead of murder. A person can be said to be acting under extreme provocation if:

1. The act of the accused that caused death was done in response to the conduct of the deceased towards or affecting the accused, and 
2. The conduct of the deceased was a serious indictable offence (meaning the deceased’s conduct constituted an offence which carried a maximum penalty of 5 years imprisonment), and 
3. The conduct of the deceased caused the accused to lose self-control, and 
4. The conduct of the deceased could have caused an ordinary person to lose self-control to the extent of intending to kill or inflict grievous bodily harm on the deceased.

The Act excludes a person from acting under extreme provocation in situations where the conduct was only a non-violent sexual advance to the accused or the accused incited the conduct in order to provide an excuse to use violence against the deceased. 

In determining whether the accused’s act that caused death was in response to extreme provocation the jury is unable to consider the accused’s self-induced intoxication. 

The loss of self-control by the accused is to be measured in accordance with an ‘ordinary person’ test. The ordinary person is one who has the minimum powers of self-control expected of an ordinary citizen who is sober, of the same age and maturity as the accused. 

The Act provides that extreme provocation is not excluded where the deceased’s conduct which formed the basis for the extreme provocation did not occur immediately before the act causing death nor is the defence not excluded merely because the act causing death was done with intent to kill or inflict grievous bodily harm.